Magnetic and electric properties of nanoparticles of Ni-substituted ferrites synthesized using a microwave refluxing process

Abstract

Microwave refluxing was found to be a suitable method to produce single phase magnetic nanoparticles of NixFe3-xO4. Ethylene glycol employed in the synthesis plays a crucial role in restricting the particle size to nano dimensions. X-ray diffraction studies, Mössbauer spectroscopy and magnetic measurements suggest that as-prepared samples were small in size (∼15 nm) and hence display low saturation magnetization values (44 - 60 emu g-1). NixFe3-xO4 transforms into γ-NiyFe2-yO3 and α-NiyFe2-yO3 after sintering at 720 and 1 020 K respectively as indicated by X-ray diffraction patterns. This was also confirmed by resistivity measurements. The electrical properties of the two transformed phases were comparable to their bulk values. It has also been found that a large substitution of Ni stabilizes γ-phase at higher temperature.